Now that temperature data for 2021 is fairly complete, a fuller picture has emerged regarding just how much the planet warmed last year. This column reported on some of the major findings last week. One of these was that global surface temperatures last were somewhere between the fifth and seventh highest ever recorded. In this 2021 joined an unbroken stretch of the hottest years recorded, stretching back to 2015. The other major finding was that the global ocean had warmed by record levels in 2021.
Apart from these findings, other datasets help give us a better understanding of how fast the Earth is heating up due to greenhouse gases (GHG) emitted by humans. The two major planet heating gases, carbon dioxide (CO2), methane (CH4) and nitrous oxide (NO2), reached record levels last year, fuelled by fossil fuel emissions, as well as agriculture and changing land use. The increase in methane concentration is a source of great worry, since it’s an even more intensive planet heating gas than CO2.
Before we get the full updates for 2021, why not predict what 2022 will bring? pic.twitter.com/vhtBjAFeGj— Gavin Schmidt (@ClimateOfGavin) January 7, 2022
According to data analysed by the independent science organisation Berkeley Earth, the world has heated by about 1.3 degree Celsius since pre-industrial times. To put this into perspective the current UN-led global effort is to limit global heating to 1.5 degree Celsius above pre-industrial times by 2100. What Berkeley Earth’s analysis also makes clear is that land areas of the planet have heated up even more: 1.8 degree Celsius on average. Such a high level of heating has been reflected in temperature records being shattered in various parts of the world, as well as an increasing number of heatwaves, droughts and wildfires.
Most observers think that current policies and commitments to reduce greenhouse emissions put us somewhere between the yellow and the light green, heading towards maybe 2.5 °C in 2100.— Dr. Robert Rohde (@RARohde) January 20, 2022
That's a better path than we had a decade ago, but still not meeting Paris Agreement goals. pic.twitter.com/chlu2mGX9D
One thing is clear: in the absence of declining global GHG emissions, this sharply rising trend of warming is going to continue, and, in fact, intensify. According to the UK’s Met Office, 2022 is going to be the eighth straight year of global temperatures being at least 1 degree Celsius higher than pre-industrial times (with the higher threshold being a likely 1.21 degree Celsius). While this may seem like a relatively low forecast, one of the Met Office’s climate scientists, Dr Doug Smith, warned that individual regions of the planet would continue to heat up more than the global average. “The fact that global average temperatures have been above 1 degree Celsius since 2015 masks the considerable temperature variation across the world. Some locations such as the Arctic have warmed by several degrees since pre-industrial times,” he said.